1. Field of the Invention
The present invention relates to a locking device for locking a heat sink to a CPU package, and particularly to a locking device for locking a heat sink to CPU packages of a range of thicknesses.
2. Brief Description of the Prior Art
FIG. 7 shows a prior art locking device, a CPU package 1 and a heat sink 2 attached to the CPU package 1. The prior art locking device comprises a bracket 4 and a plurality of pegs 3 for locking the heat sink 2 to the CPU package 1. The pegs 3 each have a stanchion 5 with a cap 13 at one end thereof and a head 6 at the other end thereof. Diameters of the heads 6 are slightly larger than those of the stanchions 5. The bracket 4 includes a flat base 11 and a plurality of longitudinally extending cantilever parts 7 extending from the base 1. The cantilever parts 7 are curved while engaging surfaces of all ends thereof are coplanar with a mating surface of the base 11. The curved cantilever parts 7 define a plurality of engaging holes 8. A plurality of slots 9 respectively extends from the engaging holes 8 oriented in a single direction. Lateral dimensions of the slots 9 are slightly larger than those of the stanchions 5 of the pegs 3 for mating with the stanchions 5. The engaging holes 8 are slightly larger than the heads 6 for receiving the heads 6. In assembly, the pegs 3 sequentially penetrate the corresponding subassemblies of the heat sink 2, the CPU package 1, and the engaging holes 8 of the bracket 4. Then, when the bracket 4 is moved slidingly along a bottom surface of the CPU package, the stanchions 5 are moved along the slots 9 and are retained in an end of the slots 9. Therefore, the pegs 3 are attached to the bracket 4 for securing the heat sink 2 and the CPU package 1 in position. With the development of new production technologies, however, PLGA type and OLGA type CPU packages of different thickness are becoming commonplace. The prior art locking device described above is only adapted for locking CPU packages of a fixed thickness. Hence, an improved locking device is required to overcome the disadvantages of the prior art.